BACKGROUND: Observational studies suggest that open visiting policies are preferred by most patients and visitors in intensive care units (ICUs), but no randomized trial has compared the safety and health outcomes of unrestrictive (UVP) and restrictive (RVP) visiting policies. The aim of this pilot, randomized trial was to compare the complications associated with UVP (single visitor with frequency and duration chosen by patient) and RVP (single visitor for 30 minutes twice a day). METHODS AND RESULTS: Two-month sequences of the 2 visiting policies were randomly alternated for 2 years in a 6-bed ICU, with 226 patients enrolled (RVP/UVP, n=115/111). Environmental microbial contamination, septic and cardiovascular complications, emotional profile, and stress hormones response were systematically assessed. Patients admitted during the randomly scheduled periods of UVP received more frequent (3.2+/-0.2 versus 2.0+/-0.0 visits per day, mean+/-SEM) and longer (2.6+/-0.2 versus 1.0+/-0.0 h/d) visits (P<0.001 for both comparisons). Despite significantly higher environmental microbial contamination during the UVP periods, septic complications were similar in the 2 periods. The risk of cardiocirculatory complications was 2-fold (odds ratio 2.0; 95% CI, 1.1 to 3.5; P=0.03) in the RVP periods, which were also associated with a nonsignificantly higher mortality rate (5.2% versus 1.8%; P=0.28). The UVP was associated with a greater reduction in anxiety score and a significantly lower increase in thyroid stimulating hormone from admission to discharge. CONCLUSIONS: Despite greater environmental microbial contamination, liberalizing visiting hours in ICUs does not increase septic complications, whereas it might reduce cardiovascular complications, possibly through reduced anxiety and more favorable hormonal profile.